More than 700,000 immigrants are waiting on applications to become U.S. citizens, a process that once typically took about six months but has stretched to more than two years in some places.
The long wait times developed after President Donald Trump took office, and some immigrant advocates are asking whether the delays might be aimed at keeping anti-Trump voters from casting ballots in elections.
The number of immigrants aspiring to become citizens surged during 2016, as Trump campaigned on an immigration crackdown. At first, the federal government kept up with the applications, but then the wait grew.
Trump on Thursday tweeted that Central American migrants in a U.S.-bound caravan should return home and apply for American citizenship if they wish.